<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>p3_CSS常用值</title>
    <style>
        h1{
            color: red;
            color: rgb(255,0,0);
            color: rgb(0,255,0);
            color: rgb(0,0,255);
            color: #ff0000;
            color: #0f0;
            color: #00f;
            color: rgba(255,0,0,1);
            color: rgba(255,0,0,0.7);
            color: rgba(255,0,0,0.5);
            color: rgba(255,0,0,.3);
            color: rgba(255,0,0,.1);
            /*color: rgba(255,0,0,0);*/
        }

        .d1{
            /*display: flex;*/
            /*justify-content: center;*/
            /*align-items: center;*/
            /*text-align: center;*/
            width: 500px;
            height: 282px;
            background-image: url("../3.jpg");
            background-repeat: no-repeat;
            background-position: 0 0;
            background-position: 100px -50px;
            background-position: center center;
            /*width-background_width*30%，height-background_height*50%*/
            background-position: 30% 50%;
            background-position: right bottom;
            background-size: 300px;
            background-color: yellow;
        }
        .d3{
            width: 600px;
            height: 400px;
            background-image: linear-gradient(90deg,red,green,blue);
            /*background-image: radial-gradient(red,green,blue);*/
        }
    </style>
</head>
<body>
<h1>测试颜色</h1>
<div class="d1"></div>
<div class="d2"></div>
<div class="d3"></div>
</body>
</html>